Disclosed are methods for fabrication of flexible circuits and electronic devices in cost effective manner that can include integration of submicron structures directly onto target substrates compatible with industrial microfabrication techniques. In one aspect, a method to fabricate an electronic device, includes depositing an electrically conductive layer on a processing substrate including a weakly-adhesive interface layer on a support substrate; depositing an insulating layer on the conductive layer to attach to the conductive layer; forming a circuit on the processing substrate by etching selected portions of the conductive layer based on a circuit design; and producing a flexible electronic device by attaching a flexible substrate to the formed circuit on the processing substrate and detaching the circuit and the flexible substrate from the interface layer, in which the flexible electronic device includes the circuit attached to the flexible substrate.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method to fabricate a flexible electronic device, comprising: depositing an electrically conductive layer on a weakly-adhesive material of a processing substrate, wherein the processing substrate includes a rigid support substrate and an interface layer comprising the weakly-adhesive material attached on the rigid support substrate; depositing an insulating layer on the conductive layer that attaches to the conductive layer; forming a circuit structure on the processing substrate by removing selected portions of the conductive layer based on a circuit design; and producing a flexible electronic device by attaching a flexible substrate to the formed circuit structure on the processing substrate and detaching the circuit structure and the flexible substrate from the weakly-adhesive material attached on the rigid support substrate without dissolution of a material of the processing substrate or the circuit structure, wherein the detaching of the circuit structure and the flexible substrate leaves the interface layer attached to the rigid support substrate to allow a further use of the processing substrate for fabricating another flexible electronic device, and wherein the flexible electronic device includes the circuit structure attached to the flexible substrate.
2. The method as in claim 1 , further comprising: forming the processing substrate by depositing the interface layer including the weakly-adhesive material on the rigid support substrate.
3. The method as in claim 1 , wherein materials used in the method include one or more of the following: the weakly-adhesive material includes poly(dimethylsiloxane) (PDMS) or polyimide; the flexible substrate includes an adhesive tape; the rigid support substrate includes a silicon (Si) wafer; the electrically conductive layer includes gold or silver; the insulating layer includes polyimide.
4. The method as in claim 1 , wherein the electrically conductive layer includes chromium, wherein the depositing the electrically conductive layer includes first depositing a gold layer on the interface layer of the processing substrate, and next depositing a chromium layer on the gold layer.
5. The method as in claim 1 , wherein the detaching includes peeling off the flexible substrate having the circuit structure attached thereto from the interface layer of the processing substrate.
6. The method as in claim 1 , further comprising: after the detaching the circuit structure and the flexible substrate from the interface layer, reusing the processing substrate to form another flexible electronic device.
7. The method as in claim 1 , wherein the processing substrate is a flexible processing substrate including the interface layer on a flexible support structure.
8. The method as in claim 7 , wherein the flexible support structure includes a polyimide material.
9. The method as in claim 1 , wherein the depositing the insulating layer on the conductive layer includes patterning the insulating layer to form a pattern mask over the conductive layer, and the removing includes wet etching the selected portions of the conductive layer that are uncovered by the pattern mask to form the circuit structure.
10. The method as in claim 1 , wherein the forming the circuit structure on the processing substrate includes laser etching the selected portions of the conductive layer and regions of the insulating layer overlaying the selected portions of the conductive layer.
11. The method as in claim 1 , wherein the formed circuit structure on the processing substrate includes a single layer circuit structure, the method further comprising: depositing a second electrically conductive layer on the formed single layer circuit structure on the processing substrate; depositing a second insulating layer on the conductive layer to attach to the second conductive layer; and forming a multi-layer circuit structure on the processing substrate by removing selected portions of the second conductive layer based on the circuit design, wherein the produced flexible electronic device includes the multi-layer circuit structure attached to the flexible substrate.
12. The method as in claim 11 , wherein the forming the multi-layer circuit includes creating at least a partial encapsulation of an insulating material on the multi-layer circuit on the processing substrate.
13. The method as in claim 12 , wherein the insulating material of the encapsulation includes polyimide; and wherein the creating the encapsulation includes depositing the polyimide on the multi-layer circuit and curing the polyimide to form the encapsulation.
14. The method as in claim 12 , wherein the encapsulation encapsulates the exposed regions of the multi-layer circuit not in contact with the processing substrate.
15. The method as in claim 1 , further comprising: attaching an electronic component at a location on the circuit structure of the flexible electronics device, wherein the attaching the electronic component on the flexible electronic device includes orienting the electronic component such that the conductive portions of the electronic component are in contact with corresponding regions of the circuit structure of the flexible electronics device.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 18, 2015
March 3, 2020
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